Technical Abstract:
Previous studies identified three major chilling-responsive proteins of 65, 60, and 14 kD whose levels increase in floral buds of blueberry during cold acclimation and decrease during deacclimation and resumption of growth. Characterization of these proteins found them to be members of a family of proteins responsive to drought and low temperature stress called dehydrins. The 65 and 60kD proteins were purified, digested into peptides, and several peptides from each were sequenced. The sequence information was used to synthesize degenerate DNA primers for amplification of a part of the gene(s) encoding these proteins. One pair of primers amplified a 200bp fragment which was cloned and sequenced. As expected, the 200 bp sequence had homology to several dehydrins from other plants. The 200 bp fragment was used to screen a cDNA library (prepared from RNA from cold acclimated blueberry floral buds) and resulted in the isolation of a cDNA clone with a 1.9 kb insert. Northern blots revealed hybridization of the 1.9 kb probe to two cold-responsive messages of 1.9 and 0.5 kb. Using 1 kb RNA:~36kD protein as a conversion factor, these messages could encode proteins of ~68 and 18kD, respectively.